The impact of pomegranate seed oil on postprandial lipemia and other cardiovascular disease risk markers in postmenopausal women

Almoraie, M. M. (2026) The impact of pomegranate seed oil on postprandial lipemia and other cardiovascular disease risk markers in postmenopausal women. PhD thesis, University of Reading. doi: 10.48683/1926.00128529

Abstract/Summary

The replacement of saturated fats with unsaturated fats is extensively recognised as an effective intervention for attenuating cardiovascular disease (CVD) risk. However, the specific health effects of individual types of unsaturated fats remain inadequately understood. To date, most research has been conducted under fasting conditions, despite individuals typically spending the majority of their day in the postprandial state. Elevated non-fasting triglyceride levels are now recognised as an independent risk determinant for CVD, particularly among postmenopausal women. Therefore, it is essential to investigate how various dietary fats influence postprandial lipid metabolism and vascular function. The literature review identified pomegranate seed waste as a promising source of bioactive compounds, including punicic acid and tocopherols. However, limited investigations have explored the phenolic profile of pomegranate seed oil (PSO) compared to other parts of the fruit, such as the peel and juice. The seeds, particularly in oil form, exhibit potential for utilisation in functional food applications. Notably, the literature review revealed a substantial gap in understanding regarding the acute effects of PSO on postprandial lipaemia, vascular function, and associated inflammatory markers in at-risk populations. Before initiating the intervention study, a detailed compositional analysis of the PSO employed in this research was conducted. Gas chromatography demonstrated that PSO contained a high concentration of punicic acid, a conjugated linolenic acid, comprising approximately 81.81% to 84.86% of the total fatty acids, along with notable levels of linoleic acid and oleic acid. Furthermore, total tocopherol content ranged from 362.69 to 397.48 mg/100 g of oil, with γ-tocopherol being the predominant isomer. Phenolic compounds were also detected in adequate concentrations. This compositional analysis provided a scientific basis for the selection of PSO as the test fat and supported its hypothesised cardioprotective potential. The PSO intervention study was designed to evaluate whether test meals enriched with PSO, compared to control meals, could beneficially modulate postprandial lipaemia (triacylglycerols (TAG)), vascular function, and inflammatory responses in postmenopausal women. In a single-blind, randomised, crossover postprandial trial, 16 postmenopausal women consumed a single test meal (0 min: 50 g fat) enriched with either PSO or the control fat on two separate occasions spaced 4 to 6 weeks apart. The primary outcome measure was postprandial TAG, with secondary measures including blood pressure, markers of endothelial function, inflammatory cytokines and metabolic parameters. We observed that the PSO-enriched meal significantly reduced postprandial TAG levels compared to the control (P < 0.001). Additionally, the PSO-enriched meal significantly augmented acetylcholine vasodilatory response (endothelium-dependent vasodilation) (P < 0.001), with a significantly greater reduction in postprandial diastolic blood pressure (P = 0.001) and a comparable result for systolic blood pressure (P = 0.048). For the postprandial pulse wave velocity (PWV), only the incremental area under the curve (iAUC) differed significantly between the test fats. These effects were accompanied by elevated postprandial plasma nitrite concentrations following PSO intake, indicating improved nitric oxide bioavailability. Furthermore, PSO consumption resulted in a reduced postprandial inflammatory response, as reflected by a lower postprandial sICAM-1 response (P < 0.001) after the PSO-enriched meal compared with the control meal. PSO also caused lower interleukin (IL)-6 production in lipopolysaccharide (LPS)-stimulated whole blood cultures (P < 0.006), with higher postprandial IL-10 production (P = 0.031) after the PSO-enriched meal than after the control meal. There were no significant differences between meals in postprandial glucose, insulin, and non-esterified fatty acid (NEFA) responses. In conclusion, this study provides novel evidence that PSO positively influences postprandial TAG levels, endothelial function (acetylcholine, endothelium-dependent vasodilation, and blood pressure), and inflammatory status in postmenopausal women. These findings may have implications for dietary fat recommendations for this population and support continued exploration of PSO as a cardioprotective functional food.

Item Type	Thesis (PhD)
URI	https://centaur.reading.ac.uk/id/eprint/128529
Identification Number/DOI	10.48683/1926.00128529
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Food and Nutritional Sciences
Date on Title Page	August 2025
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